An effort for improving device density is continuing in the fabrication of semiconductor devices. For improving the device density, it may be possible to miniaturize elements of the device and reduce the driving current of the device.
For example, in a phase-changeable memory device that uses phase changeable material as a memory element, thermal and/or electric factors may be controlled so as to control the driving current of a memory cell. Thus, various methods are being investigated for transmitting the thermal and/or electric factors efficiently through and/or between a phase-changeable material and a heating electrode.